config: watch config.json5 with inotify, reload live on change

Both config halves (Config for the memory section, AppConfig globally)
are now reloaded whenever ~/.consciousness/config.json5 changes on
disk. So edits from vim, manual tweaks, or F6's own config_writer
calls all land without a restart. No more "reload the daemon to pick
up a config change."

Wires up the previously-unused Config::reload() (Kent flagged it as
"not dead, just not wired"). Pairs it with an AppConfig reload via
install_app(). Both run on the same file-change event.

Implementation:

- notify-debouncer-mini watches the config file's parent directory
  (editors usually replace-via-rename, so watching the file itself
  misses the new inode). Debounced at 200ms to coalesce the flurry
  of events editors produce around a single save.
- Filter for events whose path is the actual config file.
- On match: call reload() for Config, run build_figment + extract for
  AppConfig. If AppConfig parsing fails (editor mid-save with partial
  content), log and keep the old cached value.
- Watcher runs in its own named thread, fire-and-forget. If startup
  fails we just log and move on — worst case is no live reload, not
  a crash.

CliArgs + SubCmd both get Clone derives so the watcher can own a
snapshot of the startup args for future reloads. Watcher is kicked
off in user/mod.rs:start() right after load_session.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/user/mod.rs

@@ -228,6 +228,9 @@ fn restore_terminal(terminal: &mut ratatui::Terminal<CrosstermBackend<io::Stdout
 async fn start(cli: crate::user::CliArgs) -> Result<()> {
     let (config, _figment) = crate::config::load_session(&cli).await?;
 
+    // Pick up external edits (vim, F6 hotkeys, etc.) without restart.
+    crate::config::watch_config(cli.clone());
+
     if config.app.debug {
         unsafe { std::env::set_var("POC_DEBUG", "1") };
     }
@@ -599,7 +602,7 @@ async fn run(
 
 use clap::{Parser, Subcommand};
 
-#[derive(Parser, Debug, Default)]
+#[derive(Parser, Debug, Default, Clone)]
 #[command(name = "consciousness", about = "Substrate-independent AI agent")]
 pub struct CliArgs {
     /// Model override (selects a named entry from `models` in config.json5)
@@ -634,7 +637,7 @@ pub struct CliArgs {
     pub command: Option<SubCmd>,
 }
 
-#[derive(Subcommand, Debug)]
+#[derive(Subcommand, Debug, Clone)]
 pub enum SubCmd {
     /// Print new output since last read and exit
     Read {